Flotation process



Patented June 14, 1932 UNITED STATES PATENT OFFICE S. HANSEN, OF INDIANAPOLIS, INDIANA, ASSIGNOR TO PETER .G. REILLY, OF

INDIANAPOLIS, INDIANA FLO'IA'I'ION PROCESS No Drawing.

This invention relates to an improved process of concentrating valuable materials by froth flotation, by the use of certain collecting agents not heretofore used.

It is the object of my invention to provide a froth-flotation process which is highly effective in the concentration of valuable materials, and one that gives a high recovery, desirably closely approaching 100%, with relatively small amounts of the collecting agent; and that is especially applicable not only to sulfid minerals and to chemical elements, but also to oxidized minerals. The term oxidized minerals as used herein is used in contradistinction to sulfid minerals; and includes the oxides, carbonates, silicates, sulfates, phosphates, molybdates, vanadates, chlorides, and bromides of the valuable metals contained in the ores.

My invention is based on the observation that the reaction products of certain unsaturated fatty substances, normally of vegetable or animal origin, with compounds havlng the composition.

1 (MON);

where M represents an element of the group comprising sulfur and selenium, are highly effective as collecting agents in the froth-flotation process for the concentration of valuable materials, and markedly so in the concentration of copper, silver, gold, and platinum. By unsaturated fatty substances as here referred to I mean those which are initially unsaturated prior to the reaction with (MCN) such as unsaturated aliphatic acids, desirably those containing from 6 to 22 carbon atoms, and certain esters, particularly the glycerides, of those acids; and include certain naturally occurring oils which contain various amounts of these ingredients, such as olive oil, (which is largely olein when sweet but contains more or less oleic acid when rancid), cotton-seed oil, cotton-seed oil foots, lard oil, which is also largely olein and/or oleic aci linseed oil, fish oils, marine-animal oils, soy-bean oil, p ippy-seed oil, rape-seed oil, and chinawood o1 These products, or the ingredients thereof Application filed March 14, 1931. Serial No. 522,790.

which are active as such collecting agents, are probably formed by a reaction at a double bond (or double bonds) in the initially unsaturated fatty substances, which reaction at a double bond may in general be represented by-the following formula:

where M, as before, represents an element of the group comprising sulfur and selenium and R and R" represents substituents (meaning either hydrogen or an organic radical) which complete the structure. If there is more than one double bond in the initial fatty substance, the reaction indicated may not be confined to a single or definite one of such double bonds.

The following compounds are a number of examples illustrating the products herein disclosed:

,flhiocyanate derivatives of undecylenic ac1 I Sdelenocyanate derivatives of undecylenic Dithiocyanate of oleic acid, Diselenocyanate of oleic acid, Thiocyanate derivatives of oleic-acid glyceride,

Selenocyanate' derivatives of oleic-acid glyceride,

Dithiocyanate of brassidic acid,

Diselenocyanate of brassidic acid,

Dithiocyanate of linoleic acid,

Diselenocyanate of linoleic acid, Hexathiocyanateof linolenic acid, Hexaselenocyanate of linolenic acid,

and glycerides of these acids, and the oils mentioned. These and other analogous compounds may be used alone and in various mixtures, and

need not be particularly pure as chemical individuals. Indeed, when prepared from the commercial oils and fats, by the treatment of such oils and fats as indicated, the resultant product is usually a mixed thiocyanate derivative or a mixed selenocyanate derivative composed of a' number of chemical individuals, as for instance these derivacyanate, as of lead for. instance, is made to' react with a halogen in an inert solvent-such as carbon tetrachloride, acetic acid, ether, carbon bisulfid, chloroform, etc-containing the unsaturated aliphatic acid. The reaction may be represented, for example, by the formulas:

where, as before, M represents an element of the group comprising sulfur and selenlum, Rre resents the unsaturated aliphatic acid or g yceride employed in the reaction and constituting at least part of the substance treated, and w represents an integer. To prevent excessive polymerization of the free thiocyanogen or selenocyanogen (MON) 2 it is desirable to carry on this reaction at a temperature of about 0 C. and in the absence of water. r

2. An alcoholic solution of an alkali or alkaline-earth thiocyanate is subjected to electrolysis at a temperature of about 0 (3., for the production of an alcoholic .solution 1 of free thiocyanogen (SCN) which is then caused to react with an unsaturated aliphatic acid, as shown in Formula 4.

3. Lead tetra-acetate is made to react with thiocyanic or selenocyanic acid, in an ethereal solution of an unsaturated aliphatic acid. The reactions involved may be represented by the following formulas:

where M, R, and m denote the same things as before.

4. A di-halogen derivative of a suitable aliphatic acid is made to react with a. basemetal thiocyanate or selenocyanate. An example of this may be represented by the following formula:

This reaction may be carried out at room temperature. Instead of the aliphatic acid bromine compound, the chlorine or iodine compound may be used.

By these general methods, a great many reaction products may be made. It suflices to give three specific examples.

5. 3.0 grams of bromine in 100 cc. of dry ether is slowly added to a suspension of 7.5

cell, such for instance as a of the mineral.

grams of lead thiocyanate in a solution of 5.0 grams of oleic acid dissolved in 50 cc. of dry ether, at a temperature of 0 to 5 (3., desirably allowed to stand for awhile to ensure substantial completion of the reaction, and then filtered. The solid residue consists substantially of lead bromide. The quantities of reagents used provide an excess of lead thiocyanate and of free thiocyanogen.

6. 5.0 grams of dibromostearic acid is added to. 5.0 grams of lead selenocyanate, and mixed well at 100 (3., or thereabout, for about two hours. This produces oleic acid diselenocyanogen, which is extracted with ether from the lead bromide residue. The

quantities used provide an excess of lead selenocyanate.

7. The process outlined in paragraph No. 5 above may be used with fish oil or olive oil instead of oleic acid.

In all of these processes, a suitable amount of (MCN) 2 is used to make the reaction substantially complete; but absolute completeness is not essential.

In the above examples the liquid reaction product as a Whole may be used as a flotation reagent; or the active principle may be concentrated by a partial or complete evaporation of the solvent used.

These various reaction products show high selectivity. and collecting power in the concentration of minerals by the froth flotation process. They may be used in the usual manner of collecting agents, with any suitable frothing agent, such as pine oil, cresylic acid or risor-rosin oil; and they may be used in an acid, alkaline, or neutral circuit; and they may be used in any t pe of flotation anney flotation cell or a Fagergren mechanical flotation machine.

The activity of the reagents produced by this process has been shown by many flotation tests.

These flotation tests were made up with 50 grams of pure chalcocite (Cu S) as the mineral, 200 cubic centimeters of distilled water, an amount equivalent to .2 pound of terpineol per ton of the mineral as a froth-producing agent, and other reagents in amounts as indicated below in pounds of reagent per ton The miniature Gates-Jocobson flotation testing cell was used as the flotation machine. The following are examples of the results obtained.

An amount of olive oil alone (neutral cirmineral in neutral circuit gave 4% recovery; whereas 0.4 pound of the fish oil (SON), derivative per ton of mineral in neutral C11- .euit gave 98% recoverfy.

Again, 04 pound 0 wood 011 per ton of mineral in neutral circuit gave no recovery of mineral; whereas 0.4 pound of the wood oil (SON) derivative per ton of mineral gave 85% recovery.

Any other suitable frothin'g agent can be used in place of ter ineol, and an acid or alkaline circuit can be used in place of a neutral circuit.

These (MCN) derivatives have also been used on a larger scale. For instance, the dithiocyanate derivative of oleic acid was employed as a collecting agent in accordance with this invention in the flotation of gold bearing sands obtained on the Colorado and San Juan rivers in the ratio of 0.02 to 0.2 pounds per ton of dry sand, with pine oil as the frothing agent, and in a slightly alkaline circuit. The sand was subjected to the ordinary flotation operation in a Fagergren mechanical flotation machine having a capacity of 1,000 pounds per hour. The head sands assayed 85 cents per cubic yard in free metallic gold, and the tailing sands 10 cents which made a recovery of 88% of the gold value of the sand. The concentrate obtained was of high grade, and assayed $293.00 per ton; and by additional cleaning of the concentrate by flotation an exceedingly high grade of refined concentrate was obtained, assaying $938.00 per ton.

I claim as my invention:

1. The process of concentrating materials by froth flotation, which consists in subjecting the unconcentrated material to froth flotation in the presence of a reaction prodnot of an initially unsaturated fatty substance having an organic-acid radical containing from 6 to 22 carbon atoms, with a compound having the structure (MCN) where M represents an element of the group comprising sulfur and selenium.

2. The process of concentrating materials by froth flotation, which consists in subjecting the unconcentrated material to froth flotation in the presence of a reaction product of an initially unsaturated fatty substance having an organic-acid radical, with a compound having the structure (MCN) where M represents an element of the group comprising sulfur and selenium.

3. The process of concentrating materials by froth flotation, which consists in subjecting the unconcentrated material to froth flotation in the presence of a reaction product of an initially unsaturated aliphatic acid containing from 6 to 22 carbon atoms, with a compound having the structure (MON) where M represents an element of the group comprising sulfur and selenium.

4. The process of concentrating materials by froth flotation, which consists in subjecting the unconcentrated material to froth flotation in the presence of a reaction product of an initially unsaturated glyceride of an aliphatic acid containing from 6 to 22 carbon atoms, with a compound having the structure (MCN) where M represents an element of the group comprising sulfur and selenium.

5. The process of concentrating materials by froth flotation, which consists in subjecting the unconcentrated material to froth flotation in the'presence of a reaction product of an initially unsaturated glyceride of an aliphatic acid, with a compound having the structure (MCN) where M represents an 7 The process of concentrating materials by froth flotation, which consists in subjecting theiunconcentrated material to froth flotation in the presence of a reaction product of an initially unsaturated fatty substance containing a substantial amount of oleic acid, with a compound having the structure (MON) 2 where M represents an element of thegroup comprising sulfur and selenium.

8. The process of concentrating materials by froth flotation, which consists in subjecting the unconcentrated material to froth flotation in the presence of a reaction product of an initially unsaturated fatty substance containing a substantial amount of olein, with a compound having the structure (MON) where M represents an element of the group comprising sulfur and selenium.

9. The process of concentrating materials by froth flotation, which consists in subjecting the unconcentrated material to froth flotation in the presence of a substance including a compound having the general formula MON MON in which R and R" represent substituents which together have between 4 and 20 carbon atoms inclusive, and M represents an element of the group comprising sulfur and selenium.

10. The process of concentrating materials by froth flotation, which consists in subjecting the unconcentrated material to froth flotation in the presence of oleic-acid-thiocyanogen.

11. The process of concentrating materials by froth flotation, which consists in subjecting the unconcentrated material to froth flotation in the presence of oleic-acid-selenocyanogen. V

12. The process of concentrating materials 6 by froth flotation, which consists in subjecting the unconcentrated material to froth flotation in the presence of olein-thiocyanogen.

13. The process of concentrating materials 10 by froth flotation, which consists in subjecting the unconcentrated material to froth flotation in the presence of olein-thiocyanogen. 14. The process of concentrating materials by froth flotation, which consists in subjecting the unconcentrated material to frotlrfiotation in the presence of a frothing agent and a reaction product of an initially unsaturated fatty substance normally of vege- 5 table or animal origin and having an organicacid radical containing from 6 to 22 carbon atoms, with a compound having the structure (MCN) where M represents an element of the group comprising sulfur and selenium. 15. iihe process of concentrating materials 25 by froth flotation, which consists in subjecting the unconcentrated material to froth flotation in the presence of a frothing agent and a reaction product of an initially unsaturated fatty substance having an organicacid radical, with a compound having the structure (MGN) where M represents an element of the group comprising sulfur and selenium.

In witness whereof I have hereunto set my hand at Indianapolis, Indiana, this 28th day of February, A. D. one thousand nine hundred and thirty-one.

MAHLIN S. HANSEN. 

